What are the prescribing instructions for scopolamine (anticholinergic) patches for an adult patient with no significant medical history for motion sickness prevention?

Scopolamine Patch Prescribing Instructions for Motion Sickness

Dosing and Application

Apply one 1.5 mg scopolamine transdermal patch to the hairless area behind one ear at least 4 hours before the antiemetic effect is required, and it can be worn for up to 3 days. 1

Specific Application Instructions

• Apply to the postauricular area (hairless skin behind one ear) on clean, dry, intact skin 1
• Only wear one patch at a time - never apply multiple patches simultaneously 1
• Do not cut the patch - this will disrupt the controlled-release mechanism 1
• Wash hands thoroughly with soap and water immediately after application to prevent accidental transfer of scopolamine to the eyes 1
• Avoid touching or applying pressure to the patch once applied, as pressure can cause scopolamine to ooze out at the edges 1

Timing Considerations

• Apply at least 4 hours before anticipated motion exposure to allow adequate time for therapeutic plasma levels to be reached 1
• Peak plasma concentrations of approximately 100 pg/mL are reached after about 8 hours, with steady-state levels maintained throughout the 72-hour wear period 2
• The patch releases scopolamine at a rate of 5 mcg/hour over 3 days 2

Extended Use Beyond 3 Days

• If therapy is required for longer than 3 days, remove the first patch and apply a new patch behind the other ear 1
• This alternating ear application helps minimize local skin irritation 1

Patch Removal and Disposal

• Remove the patch after 3 days or when motion sickness protection is no longer needed 1
• Fold the used patch in half with the sticky sides together before disposal 1
• Discard in household trash in a manner that prevents accidental contact or ingestion by children, pets, or others 1
• Wash hands and the application site with soap and water after patch removal 1

If Patch Becomes Displaced

• Discard the displaced patch immediately and apply a new patch on the hairless area behind the other ear 1
• Do not attempt to reapply a patch that has fallen off 1

Contraindications

Do not prescribe scopolamine patches to patients with:

• Angle-closure glaucoma (absolute contraindication) 1
• Known hypersensitivity to scopolamine, other belladonna alkaloids, or any component of the formulation 1

Important Warnings and Precautions

Acute Angle-Closure Glaucoma Risk

• Patients with open-angle glaucoma require monitoring of intraocular pressure during scopolamine use, as the mydriatic effect can increase intraocular pressure 1
• Instruct patients to immediately remove the patch and seek medical attention if they experience eye pain, blurred vision, visual halos, or red eyes 1

Neuropsychiatric Effects

• Scopolamine can cause psychiatric reactions including acute toxic psychosis, agitation, hallucinations, paranoia, delusions, and confusion 1
• Cognitive impairment including drowsiness, disorientation, and memory impairment for new information can occur 1, 3
• Seizures and seizure-like activity have been reported, particularly in patients with a history of seizures 1
• Elderly patients may be more sensitive to neuropsychiatric and cognitive effects 1
• Remove the patch immediately if psychiatric or severe cognitive symptoms develop 1

Visual Effects

• Blurred vision and reduced visual accommodation are common, particularly affecting near vision 1, 3
• Hypermetropic (farsighted) individuals are at particular risk for visual problems, which may worsen with repeated patch applications 3
• Avoid contact with eyes - if scopolamine gets in the eyes, it can cause pupil dilation and blurred vision 1

Gastrointestinal and Urinary Effects

• Use with caution in patients with suspected intestinal obstruction or pyloric obstruction 1
• Monitor patients with impeded urine flow or those receiving other anticholinergic drugs 1
• Discontinue if difficulty urinating develops 1

Post-Removal Withdrawal Symptoms

• Anticholinergic withdrawal symptoms may occur 24 hours or more after patch removal, including dizziness, nausea, vomiting, and headache 1
• Patients should be counseled about this possibility 1

Common Adverse Effects

Most common adverse reactions (>15% incidence) include: 1

• Dry mouth (most common)
• Drowsiness
• Blurred vision
• Pupil dilation (mydriasis)

Additional effects reported include: 1

• Dizziness
• Reduced alertness 3
• Impaired attention and memory 3
• Bradycardia 3

Special Populations

Pregnancy

• Avoid use in patients with severe preeclampsia due to risk of eclamptic seizures 1
• Scopolamine readily crosses the placenta and should only be used in pregnant women under close observation 2

Nursing Mothers

• The drug is considered compatible with nursing and is nonteratogenic 2

Elderly Patients

• Elderly patients may be more sensitive to neuropsychiatric and cognitive effects and require closer monitoring 1

Efficacy Evidence

• Scopolamine is more effective than placebo for preventing motion sickness symptoms 4, 5
• Scopolamine is the most effective single agent for motion sickness prophylaxis 2, 3
• Scopolamine is superior to methscopolamine and equivalent to antihistamines as a preventative agent 4, 5
• The transdermal system provides significant motion sickness protection similar to oral scopolamine or dimenhydrinate, but with prolonged duration 3

Clinical Pearls

• The 4-hour pre-application window is critical - patients who apply the patch too close to motion exposure may not achieve adequate protection during the initial hours 1
• Hand washing after application is essential to prevent inadvertent eye contamination, which can cause severe mydriasis and cycloplegia 1
• Dry mouth is nearly universal but is generally well-tolerated and does not require discontinuation 1, 3
• Interindividual variation in plasma levels is substantial (range 11-240 pg/mL at steady state), which may explain variable efficacy and side effect profiles 2